The present invention generally relates to actuators and, more particularly, to actuators for aircraft.
Current technology includes actuator devices movable between an operative position and inoperative position, for instance, facilitating movement of a door panel between a closed position and an open position relative to a structural member. Such devices often employ a motor and gear assembly to facilitate moving the door panel to an open position, and a spring assembly or other tension mechanism to store energy and transfer the stored energy upon extension or compression to, for example, effect closure of the door panel.
Aircraft door actuators are typically designed according to specific, predetermined load tolerances. For example, various actuators are designed to withstand in-flight loads such as low-altitude external air pressure and high-altitude internal air pressure. Other actuators are designed to withstand relatively greater loads, including high-pressure liquid forces exerted on the aircraft during de-icing processes or in-flight ice-breaking load for opening a door under emergency circumstances. In general, the weight of an actuator and the size of its components increase correlatively to its associated loads. Therefore, actuators designed for relatively significant loads are typically relatively heavy in weight and large in size, resulting in increased production and performance costs.
For example, a linear drive power door operator disclosed in U.S. Pat. No. 5,513,467 to Current et al. includes an elongate closer body housing; a power screw disposed therein; a drive; a rack and pinion assembly; a link arm; and a control device. An actuator disclosed in U.S. Pat. No. 2,387,800 to Leland et al. includes a closure member; a spring loaded shifter connected to the closure member and operative to actuate said member; a latch engaging said shifter and releasably holding it in spring loaded position; a screw shaft with a non-rotatable nut threaded thereon; and means on said nut to engage the latch and release said shaft and to strike said shifter and start it on its spring actuated movement.
As can be seen, there is a need for an improved method and apparatus, such as an actuator, to move a first member to various positions relative to a second member. Further, there is a need for such an actuator to withstand significant load forces. Finally, there is a need for such an actuator to be designed, manufactured, and transported in a cost-efficient manner while exhibiting characteristics such as a lightweight design and embodiment.